I understand the concept of using the He/Him rule for Who/Whom (He=Who, Him=Whom), but I am not sure about how to go about the following sentence for an art project:
All who can understand and accept ...

Here's the full sentence: "These men, all of who were well-known, well-respected statesmen, were viewed by their peers and common people alike as great thinkers in their day.
I just can't really see ...

I understand there has been so much on this topic but I am still confused. I get that if the person is the subject it is who and anything else is whom.
However, I'm really struggling to work out this ...

I know that who is used when asking about a subject (Who is at the door?) and whom is used when asking about an object (By whom was the door opened?). How do you determine which one to use when the ...

Making a comparison with Who/Whom I now have a doubt about the use of what with prepositions in questions. I'll explain by example:
These two sentences are correct, one is more formal than the other:
...

When I am not bound by a style that mandates otherwise, I like to use whom in dative constructions and who in accusative constructions (I am aware that English doesn't have a proper case system, but ...